Chapter 02
Manufacturing
45 terms
Practice by level
Terms
01Master production scheduleKế hoạch sản xuất chính
Definition
A schedule showing which items the plant will make, in what quantity, in which week.
Examples
- The monthly plan is 11 million 500 ml bottles, spread over 26 running days.
- The plan covers four weeks. Week one is frozen, the next three weeks can still move by up to 15 percent.
Easy to get wrong
People read the master production schedule as a sales forecast. The forecast is expected demand, the schedule is a committed run plan already capped by capacity.
02Production orderLệnh sản xuất
Definition
A document that authorises the plant to run a specific quantity, naming the item, volume, deadline and line.
Examples
- Production order 2409 014 calls for 40,000 lemon flavour bottles on line 1, due in 2 days.
- One order of 40,000 bottles matches exactly one 20,000 litre blend batch.
Easy to get wrong
A production order is not the same as a material issue slip. One order for 40,000 bottles pulls separate issue slips for bottles, caps, labels and sugar.
03Production shiftCa sản xuất
Definition
The block of time one crew runs the line before handing over to the next crew.
Examples
- The plant runs 3 shifts of 8 hours. Each shift has 450 planned running minutes and 30 minutes for breaks and handover.
- The night shift carries a 30 percent hourly premium and usually runs about 5 percent below day shift output.
Easy to get wrong
An 8 hour shift does not mean 8 hours of machine time. Planned running time is only 450 minutes, the rest goes to breaks and handover.
04Production sequencingTrình tự chạy sản xuất
Definition
The order in which jobs are placed on one line so that changeover and cleaning time stay low.
Examples
- Running pale lemon before dark cola holds changeover at 35 minutes.
- Running cola before lemon forces a full clean in place, adding 45 minutes to each change.
Easy to get wrong
People sequence by due date alone. Pushing in one rush order and breaking the light before dark rule can cost more than 2 hours of cleaning in a day.
05Run lengthĐộ dài đợt chạy
Definition
The volume or time a line runs one item without a break before switching to another item.
Examples
- The standard run for one flavour is 3 back to back shifts, about 430 thousand good bottles.
- Cutting the run to 1 shift triples the number of changeovers and costs 70 extra minutes a day.
Easy to get wrong
Long runs cut changeover time but push finished stock up. Choosing run length from one side only always gives the wrong answer.
06Minimum batch sizeQuy mô mẻ tối thiểu
Definition
The smallest quantity a piece of equipment can run at once and still give a stable result.
Examples
- The 20,000 litre blend tank has a minimum batch of 12,000 litres, below which the impeller is not covered.
- A 12,000 litre batch yields 24,000 bottles of 500 ml, against 40,000 for a full batch.
Easy to get wrong
Minimum batch size is a technical limit of plant equipment. It is different from the minimum order quantity a supplier imposes on the buyer.
07Batch productionSản xuất theo lô
Definition
A way of running where material is processed in defined batches, one batch finished before the next starts.
Examples
- Each 20,000 litre blend batch takes 40 minutes of mixing before it is pumped to the holding tank.
- One 20,000 litre batch fills 40,000 bottles and runs out in 1 hour 51 minutes at 21,600 bottles per hour.
Easy to get wrong
In batch production one formulation error hits the whole batch. A wrong parameter on a 20,000 litre batch costs 40,000 bottles, not a few units.
08Continuous productionSản xuất liên tục
Definition
A way of running where material moves through the line as an unbroken flow and output comes out at a steady rate.
Examples
- The filler runs continuously at 24,000 bottles per hour and stops only for a flavour change or a clean.
- Restarting after a stop takes 12 minutes to reach full speed, and about 300 bottles made in that window are dropped.
Easy to get wrong
Continuous production still needs lots. The plant assigns one lot code per 60 minutes of running so that a problem can be traced.
09Production lineDây chuyền sản xuất
Definition
A chain of linked machines and stations that takes material in at one end and puts packed product out at the other.
Examples
- Line 1 is 60 metres long, has 5 process steps and 12 people per shift.
- Line 1 has a design capacity of 24,000 bottles of 500 ml per hour.
Easy to get wrong
Adding people to a line does not lift output on its own. Output is capped by the slowest machine, here the filler at 24,000 bottles per hour.
10Process stepCông đoạn
Definition
One work stage on the line, with its own input, output and time.
Examples
- Line 1 has 5 process steps rated per hour at blowing 26,000, filling 24,000, labelling 25,000, case packing 27,000 and palletising 30,000.
- Labelling uses 1 person and case packing uses 3 people out of the 12 on shift.
Easy to get wrong
People add up step capacities to get line capacity. Line capacity equals the lowest step, here 24,000 bottles per hour.
11BottleneckNút thắt cổ chai
Definition
The step with the lowest capacity, which sets the output of the whole line.
Examples
- Filling at 24,000 bottles per hour is the bottleneck even though blowing reaches 26,000 and case packing 27,000.
- Lifting the labeller from 25,000 to 28,000 bottles per hour changes nothing, the line still stops at 24,000.
Easy to get wrong
The bottleneck moves after every improvement. Lift filling to 27,000 bottles per hour and blowing at 26,000 becomes the new bottleneck.
12Design capacityCông suất thiết kế
Definition
The highest output equipment can reach under standard conditions as stated by the maker.
Examples
- The filler has a design capacity of 24,000 bottles of 500 ml per hour, measured on a standard bottle with no flavour change.
- The same machine reaches only 12,000 bottles per hour on a 1.5 litre bottle because each fill takes longer.
Easy to get wrong
Design capacity is measured in ideal conditions. Multiplying 24,000 by 24 hours and promising that to sales is the fastest way to miss an order.
13Capacity utilisationHiệu suất sử dụng công suất
Definition
Actual output as a share of the maximum the plant could make in the same period.
Examples
- Theoretical capacity of 24,000 bottles per hour times 24 hours times 30 days gives 17.28 million bottles a month.
- Actual output of 11 million bottles against 17.28 million gives capacity utilisation of about 64 percent.
Easy to get wrong
Low capacity utilisation is not always bad. The plant keeps headroom for the year end peak and for maintenance windows.
14Cycle timeThời gian chu kỳ
Definition
The time between two consecutive units leaving one process step.
Examples
- A filler running 24,000 bottles per hour has a cycle time of 0.15 seconds per bottle.
- At the real speed of 21,600 bottles per hour the cycle time stretches to 0.167 seconds.
Easy to get wrong
Cycle time is not the time one bottle spends on the line. A bottle needs about 9 minutes to cross the 60 metres, yet one bottle comes out every 0.15 seconds.
15Takt timeNhịp khách hàng
Definition
The time allowed to make one unit so that demand is met exactly.
Examples
- An order of 480,000 bottles due after 24 hours of running gives a takt time of 0.18 seconds per bottle.
- A cycle time of 0.15 seconds is under the takt of 0.18 seconds, so the line can meet this order.
Easy to get wrong
Takt time is set by demand, the machine cannot change it. A machine faster than takt has spare capacity, a slower one misses the order.
16Line balancingCân bằng chuyền
Definition
Splitting work between stations so that each station takes about the same time.
Examples
- A gift pack line has 6 stations and 90 seconds of total work. The slowest station takes 20 seconds, so output is only 180 packs per hour.
- Moving work off the slowest station to bring it to 16 seconds lifts output to 225 packs per hour.
Easy to get wrong
Line output follows the slowest station, not the average. With 90 seconds over 6 stations, a 20 second station gives 75 percent balance efficiency and a 16 second station gives 93.75 percent.
17Changeover timeThời gian chuyển đổi
Definition
The time from the last good unit of the old item to the first good unit of the new item.
Examples
- Switching from lemon to orange took 90 minutes before improvement, of which 40 minutes was preparing tools and labels.
- The plant changes over 3 times a day for a total of 270 minutes, or 4.5 hours with no output.
Easy to get wrong
The changeover clock stops at the first good bottle, not at machine restart. Leaving the trial window out gives a flattering number.
18Quick changeoverChuyển đổi nhanh
Definition
A method that cuts changeover time by moving work that can be done while the machine runs out of the stopped window.
Examples
- Of the 90 minute changeover, 40 minutes went to preparing moulds and labels. Doing that before the stop leaves 50 minutes.
- Improving the strip and fit work brings it to 35 minutes, recovering 165 minutes and about 59 thousand bottles a day.
Easy to get wrong
Quick changeover starts with video and a stopwatch on each action. Buying a second tool set before measuring usually just adds cost.
19Clean in placeVệ sinh tại chỗ
Definition
Cleaning pipes and tanks by circulating solution through them without stripping the equipment.
Examples
- One clean in place cycle takes 45 minutes, uses 2,500 litres of water and costs 1.2 million dong.
- The plant runs 2 cycles a day, which is 90 minutes of the planned stop time.
Easy to get wrong
Clean in place time belongs to planned downtime. Booking it as unplanned downtime pushes the availability rate down for no real reason.
20Preventive maintenanceBảo trì phòng ngừa
Definition
Checks and part changes on a fixed schedule to reduce sudden failures.
Examples
- Line 1 stops 4 hours a week for preventive maintenance at a cost of 8 million dong.
- One sudden failure stops the line for 3 hours on average and costs 30 million dong, close to 4 times a scheduled service.
Easy to get wrong
Preventive maintenance eats running hours, so it is the first thing cut when orders are tight. Cutting 4 hours and then losing 3 hours to a breakdown loses both time and money.
21Unplanned downtimeDừng máy ngoài kế hoạch
Definition
Time the line is stopped by a fault that was not in the planned stop schedule.
Examples
- Each shift loses 45 minutes of unplanned downtime spread over 5 incidents.
- The biggest single cause is label jams at 20 minutes of those 45.
Easy to get wrong
Micro stops under 2 minutes rarely get logged. Added up over a shift they can beat one large breakdown.
22Mean time to repairThời gian sửa chữa trung bình
Definition
The average time needed to get a machine running again after a failure.
Examples
- 45 minutes of stops over 5 incidents gives a mean time to repair of 9 minutes.
- With 405 running minutes and 5 failures, the mean time between failures is 81 minutes.
Easy to get wrong
Mean time to repair measures recovery speed, not reliability. A machine that fails often but is fixed fast still shows a good number.
23FormulationCông thức sản xuất
Definition
The document giving the proportion of each ingredient and the process conditions for one product.
Examples
- The formulation for 1,000 litres of soft drink is 100 kg of sugar, 2 kg of flavour, 0.5 kg of acid and water for the rest.
- A 20,000 litre batch therefore needs exactly 2 tonnes of sugar.
Easy to get wrong
A formulation is not a bill of materials. The formulation gives process ratios, the bill of materials adds loss allowance and all packaging.
24BlendingPhối trộn
Definition
The step that mixes ingredients into a uniform batch before it goes to filling.
Examples
- A 20,000 litre batch is stirred for 40 minutes and sampled at 3 points in the tank to confirm it is uniform.
- A 20,000 litre tank feeds a filler that draws 12,000 litres per hour for 100 minutes.
Easy to get wrong
Longer mixing is not always better. Past 40 minutes more air is drawn in, which causes foam and throws off fill volume.
25FillingChiết rót
Definition
The step that puts liquid product into the pack at a set volume.
Examples
- The machine targets 502 ml for a bottle labelled 500 ml, with a tolerance of plus or minus 5 ml.
- The filler has 60 valves, so at 21,600 bottles per hour each valve fills 6 bottles a minute.
Easy to get wrong
Two extra millilitres per bottle sounds tiny. Across 143 thousand bottles a shift it is 286 litres, or 572 bottles given away.
26Primary packingĐóng gói cấp một
Definition
The step that puts product into the pack that touches it, such as a bottle, sachet or box.
Examples
- A 75 gram noodle sachet is wrapped and sealed at 400 packs per minute.
- A 500 ml PET bottle costs 1,200 dong, more than half of the 2,200 dong material cost per bottle.
Easy to get wrong
Primary packing sets the real shelf life. A 1 mm gap in the seal spoils the product early even when every earlier step passed.
27LabellingDán nhãn
Definition
The step that applies the label carrying product information to the pack.
Examples
- The labeller runs 25,000 bottles per hour and rejects any bottle with the label more than 2 mm off position.
- A label defect rate of 0.8 percent on 145,800 filled bottles a shift gives about 1,170 bottles to handle.
Easy to get wrong
A crooked label does not harm the product inside. The bottle is still sellable after the label is stripped and reapplied at 500 dong each.
28Date codingIn hạn sử dụng
Definition
The step that prints production date, expiry date and lot code onto the pack.
Examples
- The inkjet printer puts 3 lines on each noodle sachet at 400 packs per minute.
- A faint print rate of 0.3 percent on 162,000 packs a shift gives 486 packs to reject or reprint.
Easy to get wrong
A pack with an unreadable date cannot be sold even when the product inside is perfect. This defect is the cheapest to fix on the line and the most expensive once it reaches the market.
29CheckweighingCân kiểm tra khối lượng
Definition
The step that weighs every unit on the line and rejects those under or over the limit.
Examples
- A pack labelled 75 gram is rejected below 73 gram, while the current average weight is 76.5 gram.
- Pulling the average from 76.5 down to 75.8 gram saves 0.7 gram per pack, about 113 kg of flour per shift.
Easy to get wrong
Pushing the average too close to the declared weight makes the number of underweight packs climb fast. The giveaway is insurance, and cutting all of it is paid back in rejects.
30Case packingĐóng thùng
Definition
The step that places primary packs into a carton case.
Examples
- A 24 bottle case runs at 900 cases per hour when the line is at 21,600 bottles per hour.
- The carton costs 6 thousand dong, which is 250 dong per bottle.
Easy to get wrong
The case packer reaches 27,000 bottles per hour so it is not the bottleneck. Running out of cartons at the feed point still stops the whole line.
31Work in progressBán thành phẩm
Definition
Goods that have passed some steps but are not finished, still sitting inside the plant.
Examples
- At the end of the shift there are 20,000 litres in the holding tank and 30,000 filled bottles with no label.
- An unlabelled bottle carries a cost of 3,050 dong against 3,200 dong for finished goods, the difference being the 150 dong label.
Easy to get wrong
Work in progress is cash parked on the floor. Those 30,000 unlabelled bottles are over 91 million dong that cannot be sold to anyone yet.
32Line feedingCấp liệu dây chuyền
Definition
Getting material and packaging to the right station, in the right amount, at the right time so the line keeps running.
Examples
- A reel of 5,000 labels runs out after about 14 minutes at 21,600 bottles per hour.
- The line needs 900 cartons per hour, so a forklift delivers a 600 case pallet every 40 minutes.
Easy to get wrong
Being 2 minutes late every hour sounds trivial. Over a shift it is 16 minutes, more than a third of the 45 minutes of unplanned downtime.
33Buffer stock between stepsTồn đệm giữa công đoạn
Definition
Units waiting between two steps so the later step keeps running when the earlier step hiccups.
Examples
- The accumulator between filling and case packing holds 2,000 bottles, enough for 5 minutes at 400 bottles per minute.
- Raising it to 4,000 bottles covers a 10 minute fault, enough for most micro stops.
Easy to get wrong
A buffer hides faults, so it also hides problems. Too much buffer removes the signal that tells you which machine needs repair.
34Batch recordNhật ký mẻ
Definition
The file that records every parameter and every material used for one production batch.
Examples
- The record for a 20,000 litre batch holds 12 parameters, including temperature, mixing time and the lot number of each material.
- Records are kept 24 months, twice the 12 month shelf life of the product.
Easy to get wrong
The batch record is the basis for any recall. Without material lot numbers you recall a whole month of output instead of one 40,000 bottle batch.
35Overall equipment effectivenessHiệu suất thiết bị tổng thể
Definition
One index built by multiplying three parts: availability rate, performance rate and quality rate.
Examples
- Availability of 90 percent times performance of 90 percent times quality of 98 percent gives 79.4 percent.
- Lifting performance alone from 90 to 95 percent moves the index to 83.8 percent.
Easy to get wrong
The three parts multiply, so one weak part drags the whole index down. Availability of 100 percent with performance of 60 percent still lands under 60.
36Availability rateTỷ lệ sẵn sàng
Definition
The share of planned running time in which the machine actually ran.
Examples
- Planned running time is 450 minutes a shift, unplanned stops take 45 minutes, so 405 minutes run and the rate is 90 percent.
- Cutting stops from 45 to 25 minutes lifts the availability rate to 94.4 percent.
Easy to get wrong
The denominator is planned running time, not 24 hours. Using 24 hours gives a falsely low number and puts the blame on maintenance.
37Performance rateTỷ lệ hiệu năng
Definition
The share of design speed the line actually reached during the time it was running.
Examples
- Running 21,600 bottles per hour against a design of 24,000 gives a performance rate of 90 percent.
- In 405 running minutes the line produced 145,800 bottles instead of 162,000 at design speed.
Easy to get wrong
Performance drops mostly from slow running and from micro stops under 2 minutes. Neither shows up in the downtime log, which makes them hard to chase.
38YieldHiệu suất thu hồi
Definition
Actual finished output as a share of the theoretical output from the material put in.
Examples
- One tonne of flour should give 16 thousand 75 gram noodle packs. Actual output is 15,520 packs, so yield is 97 percent.
- Each percentage point of yield lost on a tonne of flour costing 9 million dong is worth 90 thousand dong.
Easy to get wrong
Yield is measured against the main material while quality rate is measured against units off the line. The two track different things and cannot be swapped.
39ScrapPhế phẩm
Definition
Product or work in progress damaged beyond repair that has to be thrown away.
Examples
- A quality rate of 98 percent means 2 percent scrap, about 2,916 bottles a shift.
- Those 2,916 bottles at a cost of 3,200 dong each is a loss of about 9.3 million dong a shift.
Easy to get wrong
Scrap at the end of the line costs far more than scrap at the start. Dropping a labelled bottle costs 3,200 dong, dropping an empty one costs 1,200 dong.
40ReworkLàm lại
Definition
Processing defective units again to bring them back to standard instead of scrapping them.
Examples
- Of the roughly 2,916 defective bottles a shift, 1,170 have label faults and are stripped and relabelled at 500 dong each.
- Reworking 1,170 bottles costs 585 thousand dong against 3.7 million dong to scrap them.
Easy to get wrong
Rework still consumes labour hours and machine hours. Booking it as free hides the true defect rate and no one fixes the root cause.
41ThroughputSản lượng đầu ra
Definition
The number of good units leaving the line per unit of time.
Examples
- The line puts out about 143 thousand good bottles a shift, which over 8 hours is about 17,900 bottles per hour.
- That 17,900 per hour sits below the machine speed of 21,600 and the design capacity of 24,000.
Easy to get wrong
Throughput counts good units only. Adding scrap back in inflates the number and hides the 2 percent defect rate.
42Conversion costChi phí chế biến
Definition
The cost of turning material into finished product, covering labour, energy, depreciation and maintenance.
Examples
- Conversion cost of 1,000 dong per bottle breaks down as labour 40, power 100, depreciation 500, maintenance 160 and utilities 200.
- At about 143 thousand good bottles a shift, conversion cost for one shift is 143 million dong.
Easy to get wrong
Conversion cost excludes the 2,200 dong of material per bottle. Mixing the two makes the 3,200 dong unit cost double count.
43Labour productivityNăng suất lao động
Definition
Good units produced per labour hour.
Examples
- 12 people on an 8 hour shift give 96 labour hours. Divide 143 thousand bottles by that and you get about 1,490 bottles per labour hour.
- Labour cost of 40 dong per bottle works out to about 5.7 million dong a shift for the 12 people.
Easy to get wrong
Labour productivity rises when the machine runs faster, not only when people work faster. Using it to score individual operators usually blames the wrong person.
44Energy per unitTiêu hao năng lượng trên đơn vị
Definition
The electricity or heat used to make one unit of product.
Examples
- Line 1 uses 0.05 kWh per bottle. At 2,000 dong per kWh that is 100 dong per bottle.
- A shift of 143 thousand bottles uses about 7,150 kWh and 14.3 million dong of electricity.
Easy to get wrong
Running slower does not cut the power bill in proportion. Idle load stays the same, so energy per bottle actually goes up.
45Trial runChạy thử sản xuất
Definition
A small run used to check formulation, equipment and speed before full production starts.
Examples
- A trial of 5,000 bottles of a new flavour takes 3 hours with a scrap rate of 12 percent against 2 percent in steady running.
- Those 3 hours cost about 65 thousand bottles of output at 21,600 bottles per hour.
Easy to get wrong
A trial eats running hours, so it is dropped when the schedule is tight. Skipping it and then losing a full 40,000 bottle batch costs many times more.